Weft thread clamp and cutter for travelling-wave shedding looms

ABSTRACT

A weft thread clamp for travelling-wave shedding looms wherein weft thread is inserted into a warp shed by means of weft inserters advancing toward the shed from spooling heads and having within a spooling station a path with the latter. The clamp comprises a body with a groove adapted to receive for reciprocation a slider carrying a rotatable follower to be engaged by a cam groove provided in a bridge stationary on the machine frame for displacing the slider between two dead centers, and further comprises means for attaching the weft thread clamp to the spooling head. The end portion of the slider protruding from the clamp body forms between two lateral walls a guideway receiving for reciprocation a first clamping jaw of said weft thread clamp which is resiliently forced into said guideway. A second clamping jaw is formed as a hook at the extremity of the slider. Said jaws are released and ready for seizing the weft thread in one of said dead centers of the path section within which the weft inserter leaves the spooling head on its way to the shed, while in the second dead center of the jaws are gripped by retracting the hook under said first clamping jaw for retaining the seized weft threaded until the next start of the process of spooling the weft thread on the weft inserter.

Unite States atent [191 Langr et a1.

1 1 Jan. 28, 1975 1 WEFT THREAD CLAMP AND CUTTER FOR TRAVELLING-WAVE SHEDDING LOOMS [73] Assignee: Vyzkumny Ustav Bavlnarslty, Usti nad Orlici, Czechoslovakia [22] Filed: June 5, 1973 [21] Appl. No.: 367,174

[52] U.S. Cl 139/12, 139/224 A, 139/122 R [51] Int. Cl D03d 47/35 [58] Field of Search 24/136 R, 115 G; 66/142,

66/151; 139/12, 13, 122 N, 122 W, 122 R, 194, 302; 242/356 R, 35.6 E

[56] References Cited UNITED STATES PATENTS 2,667,187 l/1954 Jefferson 139/263 3,384,126 5/1968 Golobart... 139/122 3,422,858 1/1969 Malchair 139/13 3,587,990 6/1971 K0stelecky.... 242/356 3,732,896 5/1973 Jekl et a1. 139/12 Primary Examiner-Henry S. .laudon 29 3s j] 1. "11" 3O 1 1 ABSTRACT A weft thread clamp for travelling-wave shedding looms wherein weft thread is inserted into a warp shed by means of weft inserters advancing toward the shed from spooling heads and having within a spooling station a path with the latter. The clamp comprises a body with a groove adapted to receive for reciprocation a slider carrying a rotatable follower to be engaged by a cam groove provided in a bridge stationary on the machine frame for displacing the slider between two dead centers, and further comprises means for attaching the weft thread clamp to the spooling head. The end portion of the slider protruding from the clamp body forms between two lateral walls a guideway receiving for reciprocation a first clamping jaw of said weft thread clamp which is resiliently forced into said guideway. A second clamping jaw is formed as a hook at the extremity'of the slider. Said jaws are released and ready for seizing the weft thread in one of said dead centers of the path section within which the weft inserter leaves the spooling head on its way to the shed, while in the second dead center of the jaws are gripped by retracting the hook under said first clamping jaw for retaining the seized weft threaded until the next start of the process of spooling the weft thread on the weft inserter.

3 Claims, 6 Drawing Figures PATENTEB I 3. 862 648 sum 30F 3 FIG. 4

WEFT THREAD CLAMP AND CUTTER FOR TRAVELLING-WAVE SHEDDTNG LOOMS The present invention relates to a weft thread clamp for travelling-wave shedding looms operated with continuous weft picking means, wherein the inserted weft length corresponds to the fabric width.

It is known that in weaving fabrics on travelling-wave shedding looms a plurality of weft inserters containing metered weft thread length to be successively inserted into fabric is continuously passed through the shed. The particular weft length corresponding to the future fabric width are spooled in operation outside the region where the actual fabric production takes place.

These necessary weft lengths are withdrawn from weft reserve packages and once spooled, as the weft inserter advances from the spooling station towards the shed, the weft thread on the inserter remains in connection with the weft reserve package and is not severed therefrom, as a rule, until engaged by at least several warp threads. In this way a weft end will arise which has to be prepared for the next process of spooling the necessary weft length on to the next weft inserter.

This is why the aforementioned severed weft thread end has to be seized by appropriate means and retained by it for a time corresponding to the overall spooling period at the most. Moreover, it is required that the weft thread end be reliably seized and retained at least till the start of the spooling process.

There are known weft seizing devices comprising two jaws of pliers loaded by a spring forcing them towards each other, the spring being disposed, as a rule, between the handles of said pliers. The pliers are provided on a slider adapted to reciprocate in a grooved body, the opposite parallel walls of the groove causing the handles to approach each other while said handles remain released when disengaged from said groove walls. The situation with the pliers jaws is just the reverse; if the handles are gripped the jaws are released, and vice versa.

A disadvantage of such an arrangement is that it lays extreme claims upon the preciseness of mating of the faces of the jaws, and that it is liable to damage or even break the weft thread when abruptly seized, so that it does not allow the necessary weft thread coils to be wound on or even prevents the spooling process from being carried at all.

It is an object of the present invention to provide a device to safeguard good performance, not to overload the retained weft thread, not to damage it, and to provide a reliable process of spooling the weft thread on to the inserter bobbin.

In order to eliminate, or at least to mitigate, the drawbacks of the prior art as hereinbefore set forth, we provide an improved weft thread clamp for a travellingwave shedding loom wherein weft thread is inserted into a warp shed by means of weft inserters advancing toward the shed from spooling heads and having within a spooling station a common path with the latter, the clamp comprising a body with a groove adapted to receive for reciprocatiion a slider carrying a rotatable follower to be engaged by a cam groove provided in a bridge stationary on the machine frame for displacing the slider between two dead centers. The mechanism of the invention further comprises means for attaching the weft thread clamp of the spooling head; in the weft thread clamp according to the invention the end portion of said slider protruding from the body forms between two lateral walls a guideway receiving for reciprocation a first clamping jaw of the weft thread clamp, resiliently forced into said guideway, a second clamping jaw being formed as a hook at the extremity of the slider. Said jaws are released and ready for seizing the weft thread in one of said dead centers of the path section within which the weft inserter leaves the spooling head on its way towards the shed, while in the second dead center the jaws are gripped by retracting the hook under said first clamping jaw for retaining the seized weft thread until the next start of the process of spooling the weft thread on to the weft inserter.

The weft thread inserter according to the invention is further characterized in that'the slider together with its hook is maneuvered by the cam groove into the one dead center in which the two clamping jaws are released and ready to seize the weft thread within the section where the paths of the spooling head and the weft inserter depart from each other and at the instance in which the weft thread, passing over an outlet peg of the weft inserter and through a guide eyelet of the spooling head, is still located downstream of the hook. A wall extension of the guideway is provided, opposite the hook, with a thread-in notch for the weft thread.

The essential advantage of the weft thread clamp according to the present invention resides in that it performs its function precisely in accordance with the preparation steps as well as the actual spooling process, wherein it reliably and fautlessly seizes the weft thread end and safely retains it. The clamp operates without any failures, is adaptable to various kinds of weft thread, and its operation is not impaired by dust deposits since they are automatically removed.

In order that the weft thread clamp according to the invention may be better understood and carried into practice, a preferred embodiment thereof will be now described with reference to the accompanying somewhat schematic drawings which, however, are not intended to limit in any way the scope of the invention. ln the drawings:

FIG. 1 is a perspective view of the weft thread clamp in its weft seizing position;

FIG. 2 is a perspective view of the weft thread clamp in its weft retaining position;

FIG. 3 shows three successive functional steps of the weft thread clamp operation relative to the weft thread and to the spooling head represented here by the weft guide eyelet only;

FIG. 4 is a fragmentary plan view of the spooling arrangement provided at the side of the shed forming mechanism;

FIG. 5 is an elevational detail view of the spooling head containing a weft reserve package, of the cam groove for the clamp follower, and of the weft inserter after the spooling process has been finished; and

FIG. 6 is an elevational detail view of the spooling head having a weft reserve package, and of the weft inserter before the start of the spooling process.

Discussing now the drawing in detail, and particularly FIGS. 1 and 2 thereof, it can be seen that a weft thread clamp l is formed with body 2 provided with a groove 3 housing a slider 4 to reciprocate therein. The slider top portion 41 which reciprocates along the groove 3, carries a stub shaft 5 on which a cam follower roll 6 is rotatably supported. The groove 3 is masked by a partly recessed cover plate 7. The opposite end portion 42 of the slider protruding from the body 2 is provided with a guideway 8 comprising lateral slide walls 9 between which a first clamping jaw 10 of the weft thread clamp 1 is received, said jaw being of U-shape in crosssection. The second clamping jaw is constituted by a hook 11 provided at the very extremity ofthe slider end portion 42. Opposite the hook 11 a slide wall extension 91 is recessed so as to form a thread-in notch 12. The first clamping jaw 10 is loaded by a wire spring 13 coiled around bolts 14 secured to the cover plate 7, and resiliently urging the first clampingjaw 10 against slider end portion 42. All the edges of the thread-in notch 12 as well as the front edges of the first clamping jaw 10 cooperating therewith are rounded off in order to prevent the weft thread 15 from being damaged when engaged thereby. It is to be understood that the first clamping jaw 10 may be also embodied as a leaf spring and the like.

On the respective lateral walls of the body 2 there are provided longitudinal webs 16 designed to be received in respective dovetail grooves formed in spooling heads 17 (FIG. 4). By means of said webs 16 the weft thread clamp 1 is attached to the trailing portion of the spooling head 17, relative to its advancing movement, so that its hool 11 points toward a weft inserter 18, viz. substantially a vertical direction (FIGS. 5 and 6). The displacement of the slider 4 together with its hook 11 is controlled by a cam groove 18 provided in a bridge 20 stationarily supported by the machine frame, and forms a guideway for the cam follower 6 to roll along. The cam groove 19 extends parallel to the path of motion of the spooling heads 17 in the direction of the arrow A from the point thereof where the spooling process terminates and where the paths of the weft inserter 18 and the spooling head 17 diverge from each other (FIG. 4) up to the point where the weft inserters 18, after having passed a weaving shed, again meet the path of the spooling heads 17 in order that the weft thread 151 shall be wound on to a bobbin 21 of the weft inserter 18.

The inserters 18 of the weft thread 151 are entrained in the direction of the arrow B (FIG. 4) into the shed of warp threads 22 within the weaving plane by a link chain 23 following a straight path under the warp and, after having passed the shed, first return along a curvilinear and the along a straight path towards a device for spooling the weft thread 151 on to the bobbins 21, which are rotatably supported by the respective weft inserter 18. During the spooling period, the weft inserters l8 follow a concurrent path together with the spooling heads 17 carried along by their own link chain 24 together with their reserve weft thread packages 25 (FIGS. 5 and 6). After a weft length 151, corresponding to the fabric width to be produced, has been wound on to the bobbin 21 of the weft inserters 18, the latter are entrained again into the travelling-wave shed, which cycle is continuously repeated.

Similarly, the spooling heads 17 together with their reserve thread packages 25 follow, in accordance with the embodiment described and shown, an endless path constituted by alternate straight and curvilinear connecting sections. This path can have a circular or oval configuration so as to allow a preparation, the spooling process proper, a control of the spooled weft thread etc. A majority of this path extending outside of the actual weaving region is concurrent with the path of the weft inserters 18, Within the aforementioned common path section of which the length depends upon the number and spacing of the particular sweft inserters 18 from each other as well as from the number of the spooling heads, the actual spooling of weft thread 151 takes place. This process is carried out by a spooling extension 26 of the spooling head 17 after the displacement of the latter into its lower or spooling position. To this purpose, the spooling head 17 is mounted for vertical adjustment on the link chain 24, and the displacement thereof between an upper and lower position is taken care of by means of a separate guide bar (not shown).

The spooling heads 17 are equipped with means necessary for leading and retaining the weft thread 15, for pulling its free end, for metering the corresponding length thereof, for winding-on, for controlling the weft, as well as for driving the particular mechanisms, or the like, These means are known per se and therefore are neither referred to nor shown in detail, since, apart from this, they are not directly related to the subject matter of the present invention.

As it can be seen in FIG. 4, the drive of the link chain 24 carrying the spooling heads 17 is derived from a sprocket 27 on a shaft '28. The link chain 23 carrying the weft inserter 18 is advanced by similar means.

The link chain 23 passes the weaving mechanisms, such mechanism comprising a rotary reed 29 provided with helical grooves 30 for inserting the thread weft into the travelling-wave shed; the weft thread 15 withdrawn from the bobbin 21 of the inserter 181 is inserted into the helical groove 30, passes through shears 31 provided adjacent the shed, and therefrom passes over a thread guide 32, through the nip of the clamp l and finally through a thread eyelet 33 to the spooling head 17.

FIG. 5 shows the spooling head 17 together with the reserve package 25 more in detail when viewed in the direction of the arrow V in FIG. 4, and also shows the weft inserter 18 and the spooling extension 26, which latter, when engaging the bobbin 21 of the weft inserter 18, will impart the rotary motion to said bobbin whereby the weft thread spooling takes place.

The movement of the slider 4 in the vertical direction is controlled by the cam groove 19 of the bridge 20, which groove at its onrun end, which is entered by the follower 6 is flared in the form of a funnel so as to facilitate the inlet of roller 6 thereinto. The cam groove 19 then follows a straight path section which is abruptly bent downwards for displacing the hook 11 to meet the path of the weft thread 15 extending from the bobbin 21 of the weft inserter 18 to the spooling head 17. After this steep course break, the cam groove 19 again assumes a straight horizontal path 191 so that the hook 11 remains in its lower position and, after having seized the weft thread 15, it is led along the slightly ascending path section of the cam groove 19 till it again attains its upper position wherein the weft thread 15 is clamped between the jaws 10 and 11. The slider 4 together with the hook 11 is brought by the cam groove 19 into the point where the jaws 10 and 11 are released and ready to seize the weft thread 15 within the region of parting of the paths A and B of the spooling head 17 and the weft inserter 18, respectively at the instant where the weft thread 15 passing over an outlet peg 36 of the weft inserter 18 and through the thread eyelet 33 of the spooling head 17, is still located downstream of the hook 11 (see the intermediate weft inserter 18 in FIG. 3). The weft thread 151 wound on the bobbin 21 is still connected with the weft thread 15 on the reserve package 25.

FIG. 6 shows the spooling head 17 together with the reserve package 25 more in detail when viewed in the direction of arrow VI in FIG. 4 just before the start of the spooling process. An end 152 of the weft thread 15, formed by severing the weft thread 151 being entrained into the shed by means of the shears 31 and wound off now from the bobbin 21, is retained by the weft thread clamp l, and the weft thread is then guided by the eyelet 33, further by the eyelets 34 and 35 to the reserve package 25 wherefrom it is then withdrawn during the spooling process. Between the spooling head 17 and the weft thread inserter 18 or its bobbin 21 no engagement via spooling extension 26 has yet occurred.

The task to be performed by the weft thread clamp l resides in seizing, by means of the hook 11, the weft thread 15 after the spooling of the weft thread has been finished and during the approach of the weft inserter 18 to the shed, and, after the weft thread 15 has been severed by the shears 31 at the beginning of weaving it in, in clamping and leading the thus arisen weft thread end 152 till the start of spooling the weft thread 151 from the same spooling head 17 on to the bobbin 21 of the weft inserter 18.

During the weft spooling process and after finishing the spooling of the weft thread 151 on to the bobbin 21 of the weft inserter 18, the two jaws 10, 11 of the weft thread clamp 1 attached to the spooling head 17, are closed by pulling out the hook 11 so that it is disengaged from the first clamping jaw the follower 6 of the weft thread clamp 1 is now disposed in its lower dead center and the weft thread is not engaged (see FIG. 3, phase I, and 1). This condition remains even at the moment when the paths of the spooling head 17 and the weft inserter 18 depart from each other. The weft thread 15 coming from the bobbin 21 is led over the outlet peg 36 of the weft inserter 18 through the guide eyelet 33 and further of the reserve package (not shown). After said paths have departed (FIG. 3, phase II), the follower 6 of the slider 4 (FIG. 1), having previously entered the cam groove 19 (FIG. 4), is conveyed by the latter into its second dead center towards the weft inserter 18 (FIG. 5) so that the hook 11 assumes its lowermost position and interferes with the path of the weft thread 15. In this moment, the jaws 10 and 11 are released. The hook remains in this position until the follower is led along the horizontal section 191 of the cam groove 19 (FIG. 5) so that the hook 11 crosses the path of the weft thread 15, catches the latter, and seizes it. Due to the ascending section of the cam groove 19, the follower 6 is displaced into its first or upper dead center so that the hook 11 is retracted below the first clamping jaw 10. Meanwhile, due to the further travel of the spooling head 17 along its curvilinear path, the hook 11 is turned so that the weft thread 15 is laid into the thread-in notch 12 (FIG. 1), guided by it, and finally inserted between the two jaws 10 and 11. Thus the weft thread 15 is retained even after the weft thread section 151 has been severed, in order to be inserted into the shed by the weft inserter 18 and to be engaged, within a starting length thereof, by several marginal warp threads 22(FIG. 3, phase III). In this way a free end 152 of the weft thread 15 is formed, which does not cease to be retained and led by clamp 1.

During further advance of the spooling head 17, said free weft thread end 152 is withdrawn back by the action of a particular mechanism (not shown) provided on the spooling head 17. An essential functional element of such a mechanism is an arm provided between the weft thread clamp I and the weft reserve package 25, and adapted to swing between two extreme positions. The weft thread 15 extending from the clamp l to said reserve package 25 is passed through the extremity of said arm.

Due to its swinging movement, the arm will form a loop from a length of the weft thread 15 terminated at the free end 152 thereof; said free end 152; however, remains entrapped between the two jaws l0 and 11; said loop will then be exhausted at the start of the new process of spooling the weft thread 151 on to the weft inserter 18, in which process said reserve of weft thread 15 is released into the new winding.

After said free weft end 152 has been built up, the arm is caused to swing by an abutment provided on the frame of the spooling heads 17. The free end 152 of the weft thread 15 is then wholly disengaged from the weft thread clamp 1 at the start of the actual process of spooling weft thread 151 on to the bobbin 21 of the weft inserter 18. This final disengagement of the free end 152 of the weft thread 15 from the clamp l is permitted by the resilient grip of said jaws 10 and 11 holding the weft thread 15, the grip being such that it is possible to withdraw the weft thread 15 by means of the afore-described mechanism of the spooling head 17.

If another type of weft thread is to be processed, the gripping force of the clamp can be easily readjusted. By this the functional cycle of the weft thread clamp 1 according to the invention is closed; the cycle will be repeated until the next length of the weft thread 151 is wound on to the bobbin 21 of the weft inserter 18.

Although the invention is illustrated and described with reference to one preferred embodiment thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a preferred embodiment, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. A weft thread clamp for travelling-wave shedding looms wherein weft thread is inserted into a warp shed by means of weft inserters advancing toward the shed from spooling heads and having within a spooling station a common path with the latter, the clamp comprising a body with a groove adapted to receive for reciprocation a slider carrying a rotatable follower to be engaged by a cam groove provided in a bridge stationary on the machine frame for displacing the slider between two dead centers, and further comprising means for attaching the weft thread clamp to the spooling head, the improvement which comprises, the end portion of the slider protruding from the clamp body forming between two lateral walls a guideway for reciprocation of a first clamping jaw of said weft thread clamp, resiliently forced into said guideway, a second clamping jaw being formed as a hook at the extremity of the slider, said jaws being released and ready for seizing the weft thread in one of said dead centers of the path section within which the weft inserter leaves the spooling head on its way to the shed, while in the second dead center the jaws are gripped by retracting the book under said first clamping jaw for retaining the seized weft thread until the next start of the process of spooling the weft thead on to the weft inserter.

8 eyelet of the spooling head is still located downstream of the hook.

3. A weft thread clamp as defined in claim 1. comprising a wall extension ofthe guideway said wall extension being provided, opposite the hook, with a threadi in notch for the weft thread. 

1. A weft thread clamp for travelling-wave shedding looms wherein weft thread is inserted into a warp shed by means of weft inserters advancing toward the shed from spooling heads and having within a spooling station a common path with the latter, the clamp comprising a body with a groove adapted to receive for reciprocation a slider carrying a rotatable follower to be engaged by a cam groove provided in a bridge stationary on the machine frame for displacing the slider between two dead centers, and further comprising means for attaching the weft thread clamp to the spooling head, the improvement which comprises, the end portion of the slider protruding from the clamp body forming between two lateral walls a guideway for reciprocation of a first clamping jaw of said weft thread clamp, resiliently forced into said guideway, a second clamping jaw being formed as a hook at the extremity of the slider, said jaws being released and ready for seizing the weft thread in one of said dead centers of the path section within which the weft inserter leaves the spooling head on its way to the shed, while in the second dead center the jaws are gripped by retracting the hook under said first clamping jaw for retaining the seized weft thread until the next start of the process of spooling the weft thead on to the weft inserter.
 2. A weft thread clamp as defined in claim 1, wherein the slider together with its hook is maneuvered by the clamp groove into the one dead center in which the two clamping jaws are released and ready to seize the weft thread, within the section where the paths of the spooling head and the weft inserter depart from each other and at the instant in which the weft thread passing over an outlet peg of the weft inserter and through a guide eyelet of the spooling head is still located downstream of the hook.
 3. A weft thread clamp as defined in claim 1, comprising a wall extension of the guideway said wall extension being provided, opposite the hook, with a thread-in notch for the weft thread. 